1. Field of the Invention
The present invention relates to a check valve assembly for use in high pressure pumps having check valve means controlling incoming and outgoing fluid flow. The check valve assembly of the present invention is especially suitable for use in reciprocating pumps or other pressure chambers operating at fluid pressures in excess of 10,000 psi, and may be adapted for use in many different types of reciprocating pumps or pressure chambers, such as electrically or engine driven crankshaft pumps, hydraulically driven fluid pressure intensifiers, and single or multiple cylinder pumps of all sizes and capacities.
2. Description of the Prior Art
Check valve assemblies are critical components in high pressure pumps because they control the flow of fluid into and out from the pressure chamber which houses the reciprocating means. The reliability of check valves is of paramount importance in the operation of high pressure pumps, since any disruption of fluid flow results in disruption of pump operation. Because existing check valves are mounted remote from a pressure chamber such that the inlet and outlet passages and the check valves are exposed to cycling high and low pressures, during intake and compression strokes, check valves and both fluid passages are vulnerable to cyclic stresses and fatigue.
Fluids may be pressurized to levels significantly in excess of 10,000 psi in high pressure reciprocating pumps. Pressure intensifiers which are known to the art are used to pressurize catalyst, water, and other fluids to pressures in excess of 50,000 psi. These types of pumps operate at high reciprocating rates, and the check valves are subject to tremendously high frequency and pressure cyclic stresses. High pressure pumps having multiple reciprocating means are also known to the art.
Inlet and outlet fluid passages located in valve bodies of commercially available high pressure pumps typically have an "L" or a "T" configuration. In an "L" configuration, inlet and outlet check valves communicate by means of valve body fluid passages which are perpendicular to each other. In a "T" arrangement, the inlet and outlet check valves are arranged opposite one another on opposite terminal ends of a valve body fluid passage represented by the top bar of the "T", while a second fluid passage, represented by the vertical bar of the "T", perpendicular to the inlet and outlet fluid passages provides communication between the pressure chamber which houses the reciprocating means and the inlet and outlet passages. In both of these existing arrangements, the inlet and outlet fluid passages are provided in a massive valve body. The check valves may be provided directly in the valve body, or they may be arranged outside of the valve body in proximity to the inlet and outlet fluid passages. High pressure pump manufacturers have also used check valve assemblies having inlet and outlet fluid passages oriented in a "V" arrangement, but material failure due to cyclic stresses from cycling high and low pressures, particularly in the inlet and outlet fluid passages have also been observed in crankshaft pumps and fluid intensifiers having fluid passages arranged in a "V" configuration.
Inlet and outlet fluid passages in high pressure pumps having either an "L" or a "T" arrangement are subjected to cyclic stresses imposed by forces generated by alternating high and low pressures common to reciprocating means. Sharp corners of the inlet and outlet passages are also subjected to high stress concentrations which often result in material fatigue and fracture. U.S. Pat. No. 4,026,322 teaches a reciprocating pump check valve assembly wherein low pressure fluid inlet passages are arranged in an angular, conical configuration terminating at the fluid inlet valve, and a fluid outlet passage is coaxially aligned with the reciprocating means in the pressure chamber. The fluid outlet passage of this check valve assembly is not protected from cyclic stresses which originate in the pressure chamber, and the fluid inlet check valve is too mechanically complex to provide reliable service.
U.S. Pat. No. 2,666,448 teaches a self-sealing relief valve having a helical spring mounted between a threaded nut and a valve member. The spring keeps the valve member seated at all times except when relieving excess pressure from within a container. U.S. Pat. No. 3,106,169 discloses an intensifier high pressure valve and block assembly having an outlet valve member which may be of a poppet valve type. U.S. Pat. No. 3,702,624 teaches a piston pump having an intake valve which is in the form of an annular valve acted upon by a spring which presses the valve upon a seat in a valve housing.
U.S. Pat. No. 3,565,191 discloses a rock-drilling apparatus having an intensifier with a piston and check valves positioned in conduit means for preventing and permitting flow of fluid. U.S. Pat. No. 3,540,349 teaches a double-acting pressure booster having check valves mounted within pressure lines. U.S. Pat. No. 3,070,023 discloses a fluid operated pump having check valves arranged to permit fluid to flow from an enclosure to a conduit.
U.S. Pat. No. 3,811,795 teaches a high pressure fluid intensifier having control valves. U.S. Pat. No. 2,942,584 teaches a reversing valve for a hydraulic reciprocating motor which has spaces on both sides of the motor piston alternately connected to the supply and exhaust of a hydraulic medium by means of a slide valve.